Crude produced in the North of Monagas Estate, EastVenezuela, has a high asphaltene content, which comes out ofsolution in both the wellbore tubulars and pipeline. This caneventually lead to complete plugging of the pipeline. Thisincreases the cost of maintaining production because of theneed to periodically remove these organic deposits. In aspecific case, 9 km of 8-5/8-in. outside diameter (OD)production pipeline was successfully cleaned out using 2-in.OD coiled-tubing (CT) to regain pipeline production. As thereis limited literature or documentation on the use of CT for thisspecific application, the operator and the service companyestablished a joint team to do the feasibility study andengineering. Some of the key points were; the design of aframe to lay down the injector head, define the entry pointsalong the pipeline, the selection of the bottomhole assembly(BHA), and fluids to use. Other issues were the measurementof stresses (push/pull) on the CT so that the CT could be runas far as possible in the pipeline without damaging either theCT or the pipeline. The pipeline was successfully cleaned, theCT being run seven times from five different entry points inthe pipeline. This resulted in savings of USD 1 million for theoperator and significantly reduced the time to recover normalproduction in the pipeline.
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